Hornwort
Ceratophyllum demersum
Hornwort is a rootless floating plant with fine whorled leaves forming long feathery stems. Fast-growing and highly tolerant, it suits all skill levels. Its cold resistance makes it an excellent companion for goldfish, which nibble its shoots without destroying it.
Parameters
- Water type
- Freshwater
- Min volume
- 20 L
- Temperature
- 15–28 °C
- pH
- 6–8
- Hardness (GH)
- 5–25 °GH
- Adult size
- 60 cm
- Difficulty
- Débutant
Environment
It thrives from 20 litres and tolerates a very wide temperature range (15 to 28 °C), pH 6 to 8, covering both tropical and coldwater tanks. Without true roots, it can float at the surface or be anchored at the bottom. Moderate lighting is sufficient.
Feeding
It draws all its nutrients directly from the water column, without substrate or roots. No CO2 is required; its rapid growth consumes nitrates and phosphates, naturally limiting algae. Light liquid fertilisation maintains dense vegetation.
Health & common diseases
Hornwort is a very robust plant, rarely subject to diseases. Its main problems are yellowing and stem melting, caused by lack of light, water that is too warm (>28°C) or excessive debris accumulation. Good water circulation and sufficient lighting (minimum 0.5 W/L) prevent these issues. Avoid excess phosphate-rich fertilisers that encourage competing algae.
Tips & tankmates
Very useful for natural filtration and as a refuge for fry, it can however proliferate: remove excess regularly. It sometimes sheds needles after a change in conditions, while acclimatising.
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Information provided for guidance only; it may vary between individuals and conditions. If in doubt about an animal's health, consult a vet.